I bought a Nano several months ago; I was able to program it successfully. Great. I bought a pair just before Christmas, and gave one to my dad. Got the software loaded onto his computer, but it got the "getsync out of sync" error. Great, nothing like buying a defective gift for the old man. Took it home, and checked the second one: both won't communicate on my laptop. I plugged in the first Nano that I bought, and it programs with no issue. So it's not a software installation on my computer. I am thinking the defective Nano's might be lacking the bootloader.

I found this link: http://arduino.cc/en/Hacking/MiniBootloader which shows how to move the bootloader on the Mini's. I am guessing that the Nano's can be programmed the same way? Same pin connections etc.

You can use one working nano board to load the bootloader onto another nano board lacking or needing a new bootloader. It's just a matter of loading the ardudinoISP sketch onto the 'programmer' nano and then making the proper wire jumpers from one nano to the other nano, then selecting the nano board in the IDE and then selecting burn bootloader option.

I have just the one good Nano, and two bad Nano's--no other boards. What bootloader option do I use for that? The AVR ISP, or the AVR ISP mkII? This link http://arduino.cc/en/Hacking/MiniBootloader has the info on the wiring, but just indicates (quickly) how to use the software.

I left my Board setting at Nano, otherwise I followed your instructions. After plugging in the USB cable, the LED (on D13, which is used for SCK) flashes seven times; it appears I need to hit reset on the "bad" Nano and then do the "Burn Bootloader" option.

I'm wondering if I need to flip MISO/MOSI. I wouldn't think so. I tried that, and get this error (much quicker than the above error, I will add):

avrdude: stk500_getsync(): not in sync: resp=0x15

***So no go on that.

***

When I plug in the USB cable, both boards will flash the LED (that is on D13, and is being used on SCK) seven times. Not sure what that means. The power LED on the "bad" Nano does light. I tried both of my "bad" Nano's with the same results. I double checked my wiring, and so far not seeing a mistake.

I have my "good" Nano plugged into a protoboard, and I have wires from D10, D11, D12, D13, +5V and GND (as supplied by the Nano, no external supply used) going to the 6 pin ICSP connector on the "bad" Nano.